According to the story, engineers say the building still saves thousands of dollars a month compared to standard design, but due to an increase of 150,000 visitors a year, the building extended its hours.

Engineers say that LEED ratings are based on predicted performance, and while the U.S. Green Building Council (USGBC) says that it has had problems obtaining usable performance data, 30 percent of buildings perform much better than expected and 25 percent perform much worse, the story stated.

As of 2008, the USGBC now requires performance reporting of all LEED buildings, the story added.